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1.
用紫外-可见光谱和Rose-Drago数据处理方法对多种新型空间不对称含咪唑基团金属Schiff碱配合物与取代四苯基卟啉锌[ZnT(p-X)PP]轴向配位反应平衡常数进行了测量。研究了配体和卟啉上取代基、反应温度等因素对平衡常数的影响, 发现各配体与锌卟啉配位反应的平衡常数与卟啉环上取代基的Hammett参数之间存在线性自由能关系。在二氯甲烷中, 利用温度系数法测量了反应体系的△rHm^○和△rsm^○。  相似文献   

2.
用Union Giken RA-401停流分光光度计对丙酮溶剂中咪唑(Im)与对位取代四苯基卟啉铁(Ⅲ)(Fe(p-X)TPPCl X=Cl,H,CH_3,OCH_3)的轴向配位快速反应动力学进行了研究.提出了反应机理.以CA-033E微机对实验数据进行处理,得到似平衡步的平衡常数K和速控步的速率常数k,并算出了似平衡步的△H、△S以及速控步活化参数△日~≠、△S~≠.发现△H、△S、△H~≠、AS~≠、InK、Ink分别与Hammett取代常数σ呈直线关系;AH~≠和△S~≠存在等动力学关系.  相似文献   

3.
徐正炎 《色谱》1993,11(4):225-226
四苯基卟啉及其铁、锰等金属配合物是一类具有较大分子量、非挥发性的卟啉衍生物。由于结构和性能上的特点,这类物质成为有机合成中一种新型催化剂。关于这类物质的裂解研究尚未见有文献报道。本文用裂解色谱法(PGC)考察了它们的热裂解  相似文献   

4.
锌卟啉配合物轴配反应的光谱及电子效应   总被引:1,自引:0,他引:1  
用紫外-可见分光光度计研究了三种新型空间不对称金属席夫碱和四种取代咪唑与间位取代四苯基卟啉锌(ZnT(m-X)PP,X=NO2,Cl,OCH3,H,CH3)在CH2Cl2中的轴向配位反应的紫外-可见吸收光谱,发现在450-700nm间存在等吸光点;采用Rose-Drago数据处理方法确定了各体系在25℃时平衡常数,发现所研究的35个配位反应体系的配位数均为1,各配体与锌卟啉配位反应的εβ/εα及平衡常数均分别与卟啉环上取代基的Hammett参数间存在线性自由能关系.  相似文献   

5.
结构对称且苯环上连有较小取代基 (硝基、卤素、烃基、甲氧基等 )的四苯基卟啉类化合物在酸性溶液中的光谱性质以及吸附在金属和半导体表面的化学反应研究引起人们的极大关注[1 3] 。从生命科学的角度考虑 ,卟啉环上连有氨基酸的四苯基卟啉较接近天然卟啉化合物[4 ,5] 。为了给天然酶的模拟研究提供信息 ,本文研究了这类卟啉衍生物H2 (p Leu)TPP在酸性溶液中的光谱性质及其吸附在AgCl溶胶表面的化学反应性质 ,并将之与H2 TPP的光谱性质进行比较。1 实验部分1 1 仪器与试剂日本岛津UV 2 2 0 1紫外 可见分光光度计 ;PH…  相似文献   

6.
为研究强磁场对卟啉类化合物的影响,以四苯基卟啉(TPP)为研究对象,比较分析了无外加磁场和强磁场条件下TPP的结晶,及Co~(2+)、Zn~(2+)与TPP的配位反应。采用X射线粉末衍射测试不同磁场强度下获得的TPP晶体,紫外分光光度计快速测定了不同磁场强度下配合物产率,并分析了配位反应的动力学。TPP的结晶度随磁场强度的增强而提高,晶体尺寸随磁场强度的增加而增大;随磁场的增强,四苯基钴卟啉(CoTPP)和四苯基锌卟啉(ZnTPP)的产率下降,但两者的反应动力学不受磁场影响,其反应速率随磁场强度提高而下降。由研究结果可知,强磁场有利于四苯基卟啉的结晶取向,四苯基卟啉在溶液中垂直于磁场取向是配位反应速率降低的主要原因,随磁场强度的增加,四苯基卟啉的取向程度提高。  相似文献   

7.
王树军 《应用化学》2010,27(6):721-726
采用紫外-可见光谱滴定法和荧光光谱法,考察了5-对硝基苯基-10,15,20-三苯基锌卟啉和5-邻硝基苯基-10,15,20-三苯基锌卟啉与3种咪唑类客体小分子进行轴向配位反应的光谱性质,并探讨取代基团在不同位置时的锌卟啉及具有不同结构特点的客体对该类轴配反应进行的影响。 实验结果表明,2种锌卟啉与咪唑类客体之间的轴配反应是按摩尔比1∶1进行,轴配反应的平衡常数均按K(2-MeIm)>K(N-MeIm)>K(Im)顺序依次减弱,其中5-邻硝基苯基-10,15,20-三苯基锌卟啉与2-甲基咪唑间的轴配反应有最大的平衡常数5.85×105 L/mol。 轴配反应的平衡常数均随温度的升高而降低,温度升高不利于平衡反应的进行。 热力学参数表明,这类反应的驱动力是焓驱动,是自发进行的配位反应。 随客体浓度的增加,5-对硝基苯基-10,15,20-三苯基锌卟啉(荧光峰位:592.9、634.2 nm)与咪唑类客体的轴配体系具有荧光增强的效应,5-邻硝基苯基-10,15,20-三苯基锌卟啉(荧光峰位:583.6、629.8 nm)与咪唑类客体的轴配体系具有荧光猝灭的效应。 轴配体系的荧光效应是由锌卟啉中硝基基团的位置所决定的,而与客体的结构特点无关。  相似文献   

8.
单取代苯丙氨酸四苯基卟啉及其配合物的合成和谱学表征   总被引:3,自引:0,他引:3  
单取代苯丙氨酸四苯基卟啉及其配合物的合成和谱学表征倪春林,王静秋,秦子斌(宜昌师范专科学校化学系,443000)(武汉大学化学系,430072)金属四苯基卟啉对某些有机底物的氧化具有催化作用,并且苯环上取代基的不同会导致其催化活性的改变[1]。单取代...  相似文献   

9.
本文首先确定卟吩的同系序数(n)和氨基取代四苯基卟啉衍生物的同系序数(N),然后将同系因子(1/2)^2^/^N与其电子活动性能(Y)作线拟合,得到一组同系线性方程:Y=a+b.(1/2)^2^/^N其中,a,b是与Y有关的常数,并用同系线性规律解释了λmax红移现象,得出了一些规律性的结论。  相似文献   

10.
锌卟啉与咪唑类配体配位反应的热力学研究   总被引:6,自引:0,他引:6  
Equilibrium constants for reactions of ZnT(p-X)PP(para-substituted zinc tetraphenylporphyrins) with ligands of the substituted imidazole in CH2Cl2 and several other solvents have been determined by visible spectral techniques, and Rose-Drago method. Electronic effects in metalloporphrins and effects of ligands, temperature and solvents were investigated. It was found that equilibrium constants for reactions of ZnT(p-X)PP with ligands follow Hammett equation. The changes of standard molar enthalpy△rHm and the changes of standard molar entropy △rSm of the reactions were obtainedfrom the plots of lnK vs. 1/T.  相似文献   

11.
设计合成了一种由卟啉与二茂铁通过共价键连接的四(对-甲酰基二茂铁-3-乙氧基)苯基卟啉化合物(Fe-PH2), 采用红外光谱、核磁共振氢谱和紫外光谱等手段对其结构进行了表征, 证实所合成的为目标产物. 紫外光谱和荧光光谱结果表明, 该卟啉体系内部给受体之间在基态下存在弱的相互作用, 而在激发态下存在较强的相互作用. 电化学测试结果表明, 连接4个二茂铁基的Fe-PH2具有更丰富的氧化还原性质.  相似文献   

12.
锌卟啉配合物;合成;meso-四-(对甲氧基)苯基卟啉和meso-四-(对甲氧基)苯基卟啉的电化学性质  相似文献   

13.
The cyclocondensation reaction between sodium 2,6-diformyl-4-methylphenolate(sdmp) and 1,5-diamino-3-(1-hydroxyethyl)azapentane (dhap) followed by in situ transmetallation with Zn(ClO4)26H2O produced a tetranuclear zinc(II)complex of the current biggest-sized [4+4] Schiff base macrocyclic ligand. The structure of the complex has been determined by X-ray techniques, indicating that the hydroxyethyl group of the amine, dhap, has been eliminated in the process. For comparison, the reaction of sdmp with diethylenetriamine has also been carried out. The resulting product has been characterized by its infrared and positive ion FAB mass spectra, which turned out to be a mixture of the corresponding [3+3] and [4+4] macrocyclic Schiff bases together with thecommon [2+2] mode.  相似文献   

14.
F-的轴向配位对(TPP)Co电化学氧化还原的影响研究   总被引:2,自引:0,他引:2  
钻卟啉的电化学氧化还原行为受轴向配位作用的影响很大[1-5]。通过循环伏安跟踪的阴离子滴定可以细致地考察此影响过程,但至今很少见文献报道[4,5].我们曾研究了Br-和Cl-存在时,(TPP)Co的电化学氧化行为特征,结果显示不同的卤离子对(TPP)Co电化学氧化还原过程的影响程度有相当大的差别[6,7].本文以循环伏安跟踪的F-滴定和光谱电化学方法研究了F-的轴向配位效应对(TPP)Co在1,2一二氯乙烷中电化学氧化还原过程的影响.1试剂与仪器1,2一二氯乙烷(DCE,北京化工厂,分析纯),在CaH。上分馏纯化后使用,四丁基高…  相似文献   

15.
1 INTRODUCTION The donor properties of pyridine N-oxide and its substituted derivatives to form metal complexes have been widely investigated[1~3]. The resulting comple- xes were used as drugs[4] and catalysts[5]. So far, there have been a few reports on the synthesis of Schiff base derived from picolinaldehyde N-oxide with se- micarbazone (PNOS Scheme 1) and its metal com- plexes. And crystal structures of the complexes of PNOS with Au(III)[6], Pd(II)[7] and Cu(II)[8] were re- …  相似文献   

16.
The title zinc(Ⅱ) complex salt [Zn(H2O)6](ClO4)2·(PNOS)4, where PNOS is derived from picolinaldehyde N-oxide with semicarbazone, has been prepared and structurally characterized by X-ray single-crystal analysis. It crystallizes in triclinic, space group P1 with a = 7.529(3),b = 10.206(4), c = 14.678(6) A, α = 86.293(6), β = 87.686(7), γ= 81.382(6)°, C28H44Cl2N16O22Zn,Mr = 1093.06, V= 1112.3(8) A3, Z = 1, Dc = 1.632 g/cm3, S = 1.089,μ(MoKα) = 0.773 mm-1 ,F(000) = 564, the final R = 0.0438 and wR = 0.1076 for 3888 independent reflections with Rint =0.0224. The crystal structure possesses a [Zn(H2O)6]2+ cation, two ClO4- anions and four PNOSs.In the crystal structure, Zn2+ cation is located at the symcenter and coordinated by six water molecules. In [Zn(H2O)6]2+, an elongate octahedral complex cation, the average Zn-O bond length is 2.087(2) A. There exist a lot of H bonds in the structure, linking the cation [Zn(H2O)6]2+, anion ClO4-and PNOS to form a 3D network.  相似文献   

17.
设计并合成了一种卟啉类光敏剂与抗癌药羟基喜树碱通过共价键相连的四(对-乙酰氧醚-10-羟基喜树碱)苯基卟啉化合物. 通过紫外光谱、 红外光谱、 核磁氢谱和质谱分析等手段对其结构进行了表征. 在癌症治疗过程中目标化合物中2种药物可能起到一定的协同效应.  相似文献   

18.
Three new zinc(II) coordination units [Zn(1–3)] based on planar-directing tetradentate Schiff base-like ligands H2(1 – 3) were synthesized. Their solid-state structures were investigated by single crystal X-ray diffraction, showing the tendency to overcome the square-planar coordination sphere by axial ligation. Affinity in solution towards axial ligation has been tested by extended spectroscopic studies, both in the absorption and emission mode. The electronic spectrum of the pyridine complex [Zn(1)(py)] has been characterized by MC-PDFT to validate the results of extended TD-DFT studies. Green emission of non-emissive solutions of [Zn(1–3)] in chloroform could be switched on in the presence of potent Lewis-bases. While interpretation in terms of an equilibrium of stacked/non-fluorescent and destacked/fluorescent species is in line with precedents from literature, the sensitivity of [Zn(1–3)] was greatly reduced. Results of a computation-based structure search allow to trace the hidden Lewis acidity of [Zn(1–3)] to a new stacking motif, resulting in a strongly enhanced stability of the dimers.  相似文献   

19.
1INTRoDUrnoNSomecomplexessynthesizedaccordingtotheideaof"combiningtheinorganicdistOrtedpoyhedronwithasymmetricconjugateorganicmo1ecules"areacategoryof,..promisingnonlinearopticalmaterialtl3.Thecomplexcrystalsareundoubtedlyanewimportantfieldfortheexplorationoffrequencydoublingandotherfunctionalmateri-alswhichwillbecomethefocusoftheworld'sattentiont2i.Inordertostudytherela-tionshipbetweenthestructure,synthesis,propertiesandapplicationsfurthermore,wereportthesynthesisandcrystalstructureofanewt…  相似文献   

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